Backgrounder: Chronology of major nuclear facility accidents

BEIJING, April 10 (Xinhua) -- Security has been a major concern in nuclear power use since the world's first nuclear plant was commissioned. The following is a chronology of disastrous accidents in the history of civilian nuclear power generation:

On Oct. 10, 1957, a fire broke out at northwest England's Windscale nuclear reactor (later renamed Sellafield), destroying the core and releasing a cloud of radioactive materials. The sale of milk and other produces from nearby farms were banned for a month. Scores of people developed cancer and died because of exposure to radiation.

On March 28, 1979, a cooling malfunction caused a partial meltdown in a reactor at the Three Mile Island nuclear plant in Pennsylvania, the United States, leading to the worst nuclear leak in the country. At least 150,000 residents were evacuated.

On April 26, 1986, one of the four reactors at the Ukraine's Chernobyl nuclear plant exploded, causing what remains the world's worst nuclear disaster. The explosion killed 30 people on the spot, released more than eight tons of radioactive materials, contaminated 60,000 square km of land, and exposed more than 3.2 million people to radiation.

On April 6, 1993, a tank containing radioactive liquid exploded at the Tomsk-7 Reprocessing Complex in the Siberian region of Russia. A total of 10 square km of land was contaminated and a number of villages were evacuated and left permanently uninhabitable.

On Sept. 30, 1999, workers at a nuclear fuel processing facility in the Japanese town of Tokaimura, 110 km northeast of Tokyo, violated safety regulations and caused a serious nuclear leak. The accident killed two workers and forced nearby residents to leave their homes.

On Aug. 9, 2004, Japan suffered its deadliest nuclear accident when a burst pipe killed at least four workers and injured seven in a commercial plant in Fukui Prefecture, 350 km west of Tokyo. The authorities said the accident led to no nuclear leak.